Hydrogen collection system and stoker furnace

Abstract

To provide: a hydrogen collection system capable of collecting a high-purity hydrogen gas; and a stoker furnace including the system.SOLUTION: According to an embodiment, there is provided a hydrogen collection system which includes: a hydrogen permeation collection pipe; a hydrogen storage part; and negative pressure means. The hydrogen permeation collection pipe is disposed at least on a grate of a stoker furnace and is hollow and is made of a metal or an alloy which is selectively permeable to hydrogen. The negative pressure means causes an internal space of the hydrogen permeation collection pipe to have negative pressure so as to transfer hydrogen from the internal space to the hydrogen storage part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a hydrogen recovery system and a stoker furnace. [Background technology]

[0002] In incinerators that burn waste such as garbage, hydrogen, water gas, hydrocarbons, etc. are generated by pyrolysis during drying and combustion of the waste. Among these, hydrogen is currently attracting attention as a method for immobilizing electricity, and demand is expected to increase in the future. Currently, hydrogen is recovered in gasification reformers at waste incineration facilities, but this method is not widely used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-228974 [Patent Document 2] International Publication No. WO01 / 04045 [Patent Document 3] Japanese Patent Application Laid-Open No. 2003-71418 [Patent Document 4] Japanese Patent Application Laid-Open No. 2013-6753 [Patent Document 5] Utility Model Registration No. 3239809 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a hydrogen recovery system capable of recovering high-purity hydrogen gas and a stoker furnace equipped with the system. [Means for solving the problem]

[0005] According to an embodiment, there is provided a hydrogen recovery system including a hydrogen permeable recovery pipe, a hydrogen storage section, and a negative pressure means. The hydrogen permeable recovery pipe is disposed at least on the grate of a stoker furnace, and is hollow and made of a metal or alloy that selectively allows hydrogen to permeate. The negative pressure means creates a negative pressure in the internal space of the hydrogen permeable recovery pipe to transfer hydrogen from the internal space to the hydrogen storage section.

[0006] According to another embodiment, there is provided a stoker furnace comprising a grate for transporting waste, a hydrogen permeable recovery pipe, a hydrogen storage section, and a negative pressure means. The hydrogen permeable recovery pipe is disposed at least on the grate and is hollow and made of a metal or alloy that selectively allows hydrogen to permeate. The negative pressure means creates a negative pressure in the internal space of the hydrogen permeable recovery pipe to transfer hydrogen from the internal space to the hydrogen storage section. [Brief explanation of the drawings]

[0007] [Figure 1] A graph showing the proportion of incineration methods in Japan. [Figure 2] 1 is a schematic perspective view illustrating a concept of mounting a hydrogen recovery system according to an embodiment on a stoker furnace. FIG. [Figure 3] FIG. 3 is a schematic perspective view in which some members are omitted from FIG. 2. [Figure 4] Conceptual diagram showing the diffusion of hydrogen atoms into a hydrogen-permeable metal material. [Figure 5] 1 is a schematic cross-sectional view conceptually illustrating an example of a waste incineration facility in which a hydrogen recovery system according to an embodiment is implemented. DETAILED DESCRIPTION OF THE INVENTION

[0008] Figure 1 shows the breakdown of incineration methods in Japan (Ministry of the Environment: Waste Treatment Technology Information, 2020 Survey Results on the Actual State of General Waste Treatment). Stoker-type incineration accounts for over 70%, but hydrogen recovery is not performed. Furthermore, existing hydrogen recovery technologies such as fractional distillation and metal permeable membranes are difficult to apply to stoker furnaces. Existing facilities for hydrogen generation and recovery are relatively large, and it is not possible to add generation and recovery functions when renovating existing facilities. For example, a gasification reformer has been devised that recovers hydrogen by chemically processing the hydrogen and hydrocarbons produced by heating waste in a low-oxygen atmosphere and recovering the purified hydrogen.

[0009] According to the embodiments described below, a hydrogen recovery system applicable to a stoker furnace and a stoker furnace equipped with the system are provided.

[0010] <Embodiment> A hydrogen recovery system according to an embodiment includes a hydrogen permeable recovery pipe, a hydrogen storage unit, and a negative pressure means. The hydrogen permeable recovery pipe is a hollow metal pipe that selectively allows hydrogen to permeate, or a hollow alloy pipe that selectively allows hydrogen to permeate. The negative pressure means transfers hydrogen from the internal space of the hydrogen permeable recovery pipe to the hydrogen storage unit by creating a negative pressure in the internal space of the hydrogen permeable recovery pipe. The hydrogen permeable recovery pipe is placed at least on the grate of the stoker furnace.

[0011] The system is a hydrogen recovery system that can be easily applied to existing stoker-type incinerators. In other words, the embodiment can provide a hydrogen recovery system for a stoker incinerator.

[0012] A stoker furnace according to an embodiment is a stoker-type incinerator equipped with the above-described hydrogen recovery system. The stoker furnace includes a grate for transporting waste, a hydrogen permeable recovery pipe, a hydrogen storage unit, and a negative pressure means. The hydrogen permeable recovery pipe is a hollow metal pipe that selectively allows hydrogen to permeate, or a hollow alloy pipe that selectively allows hydrogen to permeate. The negative pressure means transfers hydrogen from the internal space of the hydrogen permeable recovery pipe to the hydrogen storage unit by creating a negative pressure in the internal space of the hydrogen permeable recovery pipe. The hydrogen permeable recovery pipe is disposed at least above the grate.

[0013] The above-described hydrogen recovery system and stoker furnace can recover high-purity hydrogen gas in a stoker-type incinerator, which is the most popular incineration method currently used in Japan.

[0014] The hydrogen recovery using such a hydrogen recovery system and a stoker furnace can be, for example, a method for recovering hydrogen gas from a waste incinerator. The general principle of this method is to recover hydrogen gas generated by the thermal decomposition of waste using a metal or alloy pipe. Here, the property of metals or alloys that selectively allows only hydrogen, which has a small atomic size, to pass through is utilized.

[0015] More specifically, for example, in a stepped sliding stoker furnace, a metal or alloy pipe is installed at a position where the waste comes into direct contact, such as on the grate, and this pipe serves as a hydrogen permeable recovery pipe. Hydrogen generated during waste treatment is allowed to permeate into the hollow interior of the hydrogen permeable recovery pipe. Since the amount of hydrogen permeating into the hydrogen permeable recovery pipe is proportional to the difference in hydrogen partial pressure between the inside and outside of the pipe, negative pressure means such as a suction pump is used to continuously transfer hydrogen from the interior space of the pipe to a hydrogen storage unit, maintaining a reduced hydrogen partial pressure in the interior space. The hydrogen storage unit can be, for example, a gas cylinder, and the recovered hydrogen is stored therein.

[0016] According to the above method, high-purity hydrogen gas can be recovered using simple equipment. Therefore, this hydrogen recovery system can be applied to existing incinerators without requiring large-scale renovations. This makes it possible to utilize hydrogen in more efficient and useful ways than in conventional incinerators, where the generated hydrogen is simply burned in the furnace.

[0017] The stoker furnace to which the hydrogen recovery system is applied and the stoker furnace described above are not limited to waste incinerators. For example, the recovery system according to the embodiment can also be applied to a stoker-type combustion furnace that uses coal as fuel.

[0018] Hereinafter, embodiments will be described with reference to the drawings. Note that common components throughout the embodiments are designated by the same reference numerals, and redundant explanations will be omitted. Each figure is a schematic diagram intended to facilitate explanation and understanding of the embodiments, and while the shapes, dimensions, ratios, etc. may differ in some places from the actual device, these can be appropriately modified in design, taking into consideration the following explanation and known techniques.

[0019] Figures 2 and 3 show the concept of implementing a hydrogen recovery system according to an embodiment in a stoker furnace. Figure 2 shows an example of application of a hydrogen recovery system to a stoker (fire grate) in a step-sliding stoker furnace. Figure 3 shows a state in which some components are omitted from Figure 2, revealing parts that were hidden in Figure 2.

[0020] As shown in each figure, an example hydrogen recovery system includes a hydrogen permeable recovery pipe 1, a hydrogen lead pipe 2, a suction pump 3, and a hydrogen storage cylinder 4. The suction pump 3 has an inlet 31 connected to the hydrogen permeable recovery pipe 1 via the hydrogen lead pipe 2, and an outlet 32 ​​connected to the hydrogen storage cylinder 4, an example of a hydrogen storage unit, via the hydrogen lead pipe 2. A gate valve 5 is provided in the hydrogen lead pipe 2 between the suction pump 3 and the hydrogen storage cylinder 4. The suction pump 3 draws hydrogen that has permeated into the internal space of the hydrogen permeable recovery pipe 1 and transfers it to the hydrogen storage cylinder 4. Because the hydrogen permeable recovery pipe 1 is sealed except for the portion connected to the suction pump 3 via the hydrogen lead pipe 2, the internal space of the hydrogen permeable recovery pipe 1 becomes negative pressure when the suction pump 3 is operated. The hydrogen lead pipe 2 has a hollow structure, and its internal space serves as a flow path for transferring hydrogen from the hydrogen permeable recovery pipe 1 to the hydrogen storage cylinder 4 via the suction pump 3. That is, the illustrated hydrogen recovery system is equipped with a negative pressure means consisting of a hydrogen delivery pipe 2 and a suction pump 3. When the hydrogen storage cylinder 4 is replaced or when the hydrogen storage cylinder 4 is removed to apply the recovered hydrogen to resource utilization or other purposes, the gate valve 5 can be closed. Although only one gate valve 5 is shown in the illustrated example, gate valves and other valves can be provided in various locations for reasons such as isolating the hydrogen flow path when inspecting various parts. Note that the suction pump 3 alone can be defined as the negative pressure means, without including the hydrogen delivery pipe 2.

[0021] A typical stoker furnace includes alternating fixed and movable grates, and the sliding of the movable grates agitates and transports the waste. In the illustrated example, only the fixed grate 6 and the movable grate 7 are shown as a concept of the stoker, and other furnace components are omitted. The sliding direction of the movable grate 7 in Figure 2 is from the upper left to the lower right of the figure, and the waste is transported on the stoker from the upper left to the lower right. In Figure 3, the movable grate 7 is omitted to show the portion hidden under the movable grate 7, but for convenience in the following explanation, the direction from the upper left to the lower right of the figure will be referred to as the sliding direction.

[0022] As the movable grate 7 protrudes forward from the end of the upper fixed grate 6 and slides downward and to the right so as to increase its overlap with the top surface of the lower fixed grate 6, it pushes the waste resting on the top surface of the lower fixed grate 6 downward and to the right, causing the waste to fall from the end of the fixed grate 6 onto the top surface of the lower movable grate 7. As the movable grate 7 slides upward and to the left so as to pull it back under the upper fixed grate 6, the waste resting on the top surface of the movable grate 7 is pressed against the side of the end of the upper fixed grate 6 and falls from the end of the movable grate 7 onto the top surface of the lower fixed grate 6. In this way, the waste is transported by the sliding of the movable grate 7.

[0023] The hydrogen permeable recovery pipes 1 of the hydrogen recovery system are installed on the top surface of the fixed grate 6 so that their longitudinal direction is along the sliding direction of the movable grate 7. In the example shown, most of the hydrogen permeable recovery pipes 1 bend downward from the edge of the fixed grate 6 at the end of the fixed grate 6 on the downstream side in the waste transport direction, then turn back upward to form a U-shaped hanging portion, and then meet up on the upstream side and follow the top surface of the fixed grate 6. However, there is one hydrogen permeable recovery pipe 1 along the edge of the fixed grate 6 at the back right of each figure that does not turn back and ends at the end of the fixed grate 6.

[0024] The lower surface of the movable grate 7 is provided with grooves 71 that correspond to the respective hydrogen permeable recovery pipes 1 and extend along the sliding direction. Each groove 71 is wider than or equal to the diameter of the hydrogen permeable recovery pipe 1, and the movable grate 7 covers the upper surface of the fixed grate 6 so that each hydrogen permeable recovery pipe 1 overlaps its corresponding groove 71. The provision of the grooves 71 on the lower surface of the movable grate 7 prevents interference between the hydrogen permeable recovery pipes 1 installed on the upper surface of the fixed grate 6 and the movable grate 7. Furthermore, the direction in which the hydrogen permeable recovery pipes 1 extend on the upper surface of the fixed grate 6 and the direction in which the grooves 71 extend on the lower surface of the movable grate 7 both align with the sliding direction of the fixed grate 6, allowing the movable grate 7 to slide without interfering with the hydrogen permeable recovery pipes 1. In the illustrated example, the grooves 71 have a semicircular cross section, but the shape of the grooves is not limited to this. From the perspective of efficiently transporting waste and preventing waste from entering the grooves 71, it is preferable that the shape and dimensions of the grooves 71 be similar to the outer shape and dimensions of the hydrogen permeable recovery pipes 1.

[0025] The shape and arrangement of the hydrogen permeable recovery pipes 1 are not limited to the example shown in the figure, as long as they do not interfere with the sliding of the movable grate 7. For example, all of the hydrogen permeable recovery pipes 1 may be configured to fold back at the downstream end of the fixed grate 6, or none of the hydrogen permeable recovery pipes 1 may be configured to fold back. Alternatively, the hydrogen permeable recovery pipes 1 may fold back without bending downward so as to hang from the edge of the fixed grate 6. Additionally, as shown in FIG. 3, multiple hydrogen permeable recovery pipes 1 are connected to the hydrogen conduit 2 at the end of the fixed grate 6 located upstream of the waste transport. However, instead of the structure in which multiple hydrogen permeable recovery pipes 1 branch off from the hydrogen conduit 2 as in this example, a single hydrogen permeable recovery pipe 1 may be configured to fold back multiple times and travel back and forth over the top surface of the fixed grate 6. However, it is desirable to select an appropriate structure taking into account factors such as interference with the sliding movable grate 7 and durability against the weight of the waste transported on the stoker.

[0026] In the above example, the hydrogen permeable recovery pipe 1 is only shown positioned on the main surface of the upper side of the fixed grate 6, but the hydrogen permeable recovery pipe 1 may be installed in other locations. For example, the hydrogen permeable recovery pipe may be installed on the upper surface of the movable grate 7. In this case, the hydrogen permeable recovery pipe on the movable grate 7 moves in the furnace together with the movable grate 7, so the design of the hydrogen permeable recovery pipe and the hydrogen conduction pipe should be selected appropriately. Furthermore, to prevent the hydrogen permeable recovery pipe from interfering with the fixed grate 6 as the movable grate 7 slides, a groove may be provided, for example, on the underside of the fixed grate 6. The hydrogen permeable recovery pipe may also be installed in locations other than the upper surface of the grate. However, since hydrogen is generated by incomplete combustion in an environment with low oxygen concentration, it is desirable to install the hydrogen permeable recovery pipe on or near the grate because hydrogen is generated in large amounts from waste buried under other waste and therefore less oxygen is supplied to the waste near the grate. For example, the hydrogen permeation recovery pipe can be installed on the end side of the grate downstream in the direction of waste transport, i.e., on the part that corresponds to the riser if the grate is considered to be a step in a staircase, or on the inner wall surface of the furnace near the grate.

[0027] The concept of hydrogen permeation into the hydrogen permeation recovery tube 1 of a furnace is shown in FIG. 4. FIG. 4 is a conceptual diagram illustrating the diffusion of hydrogen atoms into a hydrogen-permeable metal material. Hydrogen molecules 20 can pass through a hydrogen-permeable metal material (a material made of a metal or alloy) wall 10 from the high-hydrogen partial pressure side to the low-hydrogen partial pressure side (from left to right in the figure) due to a pressure gradient, for example, in a temperature environment of 300°C or higher. Specifically, at temperatures of 300°C or higher, the hydrogen molecules 20 split into hydrogen atoms 21 and diffuse into the voids 12 between the metal atoms 11 that make up the wall 10. The hydrogen atoms 21 that diffuse into the voids 12 migrate to the low-hydrogen partial pressure side of the wall 10 and recombine to form hydrogen molecules 20. This allows hydrogen to selectively permeate. The hydrogen recovery system according to the embodiment utilizes this phenomenon to recover hydrogen. That is, the wall of the hydrogen permeation recovery tube 1 corresponds to the wall 10 shown in FIG. 4, and the internal space of the hydrogen permeation recovery tube 1 corresponds to the low-hydrogen partial pressure side of the wall 10 shown on the right. The hydrogen that has permeated into the internal space of the hydrogen permeation recovery pipe 1 is moved to a hydrogen storage section (e.g., a hydrogen storage cylinder 4) by a negative pressure means including a suction pump 3, etc., so that the hydrogen partial pressure inside the hydrogen permeation recovery pipe 1 is lowered, creating a difference in hydrogen partial pressure relative to the outside of the pipe.

[0028] If there is a difference in hydrogen partial pressure between the inside and outside of the hydrogen permeable recovery tube 1, hydrogen can permeate from the periphery of the hydrogen permeable recovery tube 1 into the tube's interior. It is not necessary to create a vacuum in the internal space of the hydrogen permeable recovery tube 1. Furthermore, a hydrogen permeable recovery tube 1 with a thinner tube wall exhibits higher permeability. Considering the strength required for the tube wall to maintain a vacuum in the internal space, a certain thickness or greater is required, which limits the improvement of permeability. In addition to the negative pressure inside the tube, for reasons such as the physical strength relative to the weight of the waste and the high temperature environment inside the furnace, it is desirable from the perspective of strength to have a tube wall thickness of at least a certain thickness. Therefore, it can be said that there is a trade-off between hydrogen permeability and tube strength depending on the tube wall thickness.

[0029] When no combustion is occurring in the furnace, i.e., when the incinerator is not operating, hydrogen is not generated, so there is no need to maintain a negative pressure in the internal space of the hydrogen permeation recovery pipe 1 using a negative pressure means. For example, the suction pump 3 can be started after waste is placed on the grate, creating a difference in hydrogen partial pressure between the inside and outside of the hydrogen permeation recovery pipe 1 before hydrogen begins to be generated due to the drying and combustion (incomplete combustion) of the waste, allowing the generated hydrogen to be recovered. Alternatively, in consideration of the possibility that hydrogen that permeated into the hydrogen permeation recovery pipe 1 during the previous operation may remain, the suction pump 3 can be started before the waste reaches the grate. Many incinerators require time for both startup and shutdown, and therefore operate for long periods of time (e.g., several months of continuous 24-hour operation). During this period, the internal space of the hydrogen permeation recovery pipe 1 is constantly maintained at a negative pressure.

[0030] Corrosive gases such as hydrogen sulfide may be generated inside the furnace. Therefore, it is preferable that the material of the hydrogen permeation recovery pipe 1 is corrosion-resistant. An example of a hollow pipe that is hydrogen permeable and corrosion-resistant is a stainless steel pipe made of stainless steel such as SUS316L.

[0031] In a typical incinerator without hydrogen recovery, the generated hydrogen is burned in the furnace along with other combustible gases. In a furnace with a hydrogen recovery system, the hydrogen is recovered without being burned, which can reduce the combustion temperature in the furnace. This reduction in combustion temperature can be addressed, for example, by adjusting the amount of air supplied to the furnace.

[0032] An example of application of the recovery system according to the embodiment to a stoker-type waste incinerator is shown in Fig. 5. Fig. 5 conceptually illustrates an example of a waste incineration facility equipped with the hydrogen recovery system. The waste incineration facility may be a facility including a stoker furnace according to the embodiment.

[0033] The illustrated waste incineration facility 100 includes a waste receiving and supply facility 110, a combustion facility 120 for incinerating the waste, a boiler facility 130 for generating steam using heat generated by the combustion, a power generation facility 140 for generating electricity using the steam generated by the boiler facility 130, a flue gas cooling tower 150 for reducing thermal pollution caused by the exhaust gas emitted from the boiler facility 130, a dust collector 160 for removing ash and dust remaining in the exhaust gas, a chimney 170 for discharging the exhaust gas treated by the flue gas cooling tower 150 and the dust collector 160 outside the facility, and an ash discharge facility 180 for collecting and disposing of incineration residues including ash and dust. Of these, all components except the power generation facility 140, the chimney 170, and the ash discharge facility 180 each constitute a part of an incinerator. Note that FIG. 5 merely illustrates the waste incineration facility 100 conceptually, and the relative positions and dimensions of each component may differ from those of an actual facility. In particular, outlines of the power generation equipment 140, chimney 170, and ash discharge equipment 180 located outside the incinerator are omitted.

[0034] Waste collected by waste collectors and the like is delivered to the waste incineration facility 100 via a receiving and supply facility 110, where it is temporarily stored until it is sequentially introduced into the incineration facility 120 for incineration treatment. Specifically, waste is delivered into the receiving and supply facility 110 via an inlet 111 and temporarily stored in a first waste pit 112 and a second waste pit 113. For example, waste arriving at the waste incineration facility 100 is first delivered via the inlet 111 to the first waste pit 112, and then transferred from the first waste pit to the second waste pit 113 by a waste crane 114 while being agitated. Typically, the waste is agitated and homogenized before being subjected to the incineration treatment to ensure stable combustion. Once the waste is ready for incineration treatment, it is delivered by the waste crane 114 to a waste input hopper 121, which is the entrance to the incineration facility 120. The delivery of waste to the receiving and supply facility 110 and the general route the waste takes within the receiving and supply facility 110 are indicated by arrow W1.

[0035] The illustrated combustion equipment 120 includes the waste input hopper 121 and a stoker-type combustion furnace 122. The combustion furnace 122 includes a grate 123 for transporting the waste. The grate 123 includes fixed grates and movable grates arranged alternately, but FIG. 5 simply depicts the fixed grates and movable grates without distinguishing between them. A dust feeder 124 is provided below the waste input hopper 121, which pushes the waste input into the hopper onto the most upstream grate 123. Combustion air 128 is supplied into the combustion furnace 122 from below the grate 123, and the waste is burned by radiant heat within the furnace.

[0036] Specifically, from the upstream side to the downstream side of the transport of waste on the grate 123 indicated by arrow W2, the area above the grate 123 is divided into a drying zone 125, a combustion zone 126, and a post-combustion zone 127. In the most upstream drying zone 125, drying of the waste progresses, and in the downstream combustion zone 126, the dried waste ignites and main combustion takes place, and in the most downstream post-combustion zone 127, the remaining waste is completely combusted. Because the largest amount of hydrogen is generated in the drying zone 125, it is desirable to install hydrogen permeation recovery pipes at least in the grate 123 in the drying zone 125. In the illustrated example, the hydrogen recovery system is applied only to the drying zone 125, but it is also possible to apply the hydrogen recovery system to the combustion zone 126 and install hydrogen permeation recovery pipes in the grate 123. Almost no hydrogen is generated in the post-combustion zone 127.

[0037] High-temperature gas 129 produced by combustion in the combustion furnace 122 is supplied to a boiler 132 in a boiler facility 130 and is used to heat water / steam. Combustion residues such as incineration ash obtained by complete combustion of the waste in the post-combustion zone 127 are sent to an ash discharge facility 180 as shown by arrow W3.

[0038] Many waste incineration facilities effectively utilize the heat generated by the incineration of waste to generate electricity. In the boiler equipment 130 of the illustrated waste incineration facility 100, water is heated using heat generated in the combustion equipment 120 to produce steam that is used to generate electricity in the power generation equipment 140. The boiler equipment 130 includes a boiler 132, a steam drum 134, a superheater 136, and an economizer 138. The boiler equipment 130 also includes a water feed pipe 131 that supplies water to the boiler 132, an evaporation pipe 133 installed in the boiler 132, a steam pipe 135 that serves as a steam flow path, a superheater tube 137 installed in the superheater 136, and a reheater tube 139 installed in the economizer 138.

[0039] Water is supplied to the boiler 132 through a water supply pipe 131. More specifically, the water supply pipe 131 is connected to an evaporation pipe 133 installed in the boiler 132, and water is supplied into the evaporation pipe 133. The water supplied to the evaporation pipe 133 is heated by high-temperature gas 129 supplied from the combustion furnace 122, and at least a portion of the water is converted into steam. The steam or a mixture of liquid water and steam obtained by heating in the evaporation pipe 133 is supplied to a steam drum 134, where the liquid water and steam are separated. The steam is sent to a superheater 136 through a steam pipe 135. The liquid water can be supplied again to the boiler 132 through the water supply pipe 131. Alternatively, the water can be sent to a facility external to the incinerator, such as a water treatment facility. The water supply pipe 131 can also supply water to the boiler 132 from a water source external to the incinerator.

[0040] In the superheater 136, the steam flows through superheater tubes 137 that communicate with the steam pipe 135, and the steam is further heated. The superheater 136 is supplied with the high-temperature gas 129 that has passed through the boiler 132, and uses the heat to heat the steam to a higher temperature. The steam is then sent to a power generation facility 140, where it is used to generate electricity, for example, by rotating a turbine.

[0041] The steam used for power generation in the power generation equipment 140 is returned to the incinerator and sent to the economizer 138. Within the economizer 138, the steam flows through a reheater tube 139 and is reheated by the residual heat of the high-temperature gas 129 supplied from the superheater 136. The reheated steam is returned to the steam drum 134 through a steam pipe 135. The use of the economizer 138 makes it possible to make maximum use of the heat generated in the incinerator 122. Because the gas still retains heat after passing through the economizer 138, the flue gas G is sent to a flue gas cooling tower 150 to reduce thermal pollution.

[0042] In the exhaust gas cooling tower 150, the temperature of the exhaust gas G is reduced, for example, by spraying cooling water. The exhaust gas G after being cooled is sent to a dust collector 160, where ash, dust, etc. remaining in the exhaust gas G are removed. In the dust collector 160, the exhaust gas G is filtered to remove ash and dust, for example, by passing the exhaust gas G through a bag filter 161. The exhaust gas G, whose environmental impact has been reduced by cooling it and removing dust, etc., is discharged outside the waste incineration facility 100 through a chimney 170. Although not shown in the figure, a portion of the exhaust gas can be recirculated to the combustion furnace 122.

[0043] Dust collection hoppers 169 are provided below the superheater 136, the economizer 138, the exhaust gas cooling tower 150, and the dust collector 160, and ash, dust, etc. that have fallen off from the high-temperature gas 129 / exhaust gas G are accumulated in the dust collection hoppers 169. The ash, dust, etc. that have accumulated in the dust collection hoppers 169 at each location are sent to an ash removal facility 180 as shown by arrow W4.

[0044] The ash removal facility 180 processes incineration residues such as ash and dust sent from the waste incineration facility 100. Through the processing, for example, molten slag is obtained, which can be reused as aggregate for concrete, etc.

[0045] The waste incineration facility 100 is merely an example of a specific operation of the hydrogen recovery system according to the embodiment, and the incineration facility in which the hydrogen recovery system can be installed is not limited to the one shown in the figure. Furthermore, the design of the stoker furnace according to the embodiment is not limited to the one shown in the figure.

[0046] <Modification> Hydrogen can be recovered even when a recovery system equipped with a hydrogen permeable recovery pipe, a hydrogen storage unit, and a negative pressure means similar to those in the hydrogen recovery system according to the above embodiment is installed in a combustion furnace other than a stoker furnace. For example, hydrogen can be recovered using the same principle as in the above embodiment by installing a hydrogen permeable recovery pipe in a position buried in the waste in an incinerator without a grate. Furthermore, in a gasification furnace, for example, by installing a hydrogen permeable recovery pipe modified into a coil shape inside the furnace, hydrogen recovery functionality can be added without the need for large-scale modifications like those required for a gasification reforming furnace.

[0047] According to one or more of the above-described embodiments, a hydrogen recovery system and a stoker furnace equipped with the system are provided. The hydrogen recovery system includes a hollow hydrogen permeable recovery pipe, a hydrogen storage unit, and a negative pressure means. The hydrogen permeable recovery pipe is disposed at least on the grate and is made of a metal or alloy that selectively allows hydrogen to permeate. The negative pressure means creates a negative pressure in the internal space of the hydrogen permeable recovery pipe to transfer hydrogen from the internal space to the hydrogen storage unit. The hydrogen recovery system and the stoker furnace equipped with the system are capable of recovering high-purity hydrogen gas.

[0048] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0049] 1...hydrogen permeation recovery pipe, 2...hydrogen conduction pipe, 3...suction pump, 4...hydrogen storage cylinder, 5...gate valve, 6...fixed grate, 7...movable grate, 10...wall, 11...metal atom, 12...void, 20...hydrogen molecule, 21...hydrogen atom, 71...groove, 100...waste incineration facility, 110...receiving and supply equipment, 111...feeding port, 112...first waste pit, 113...second waste pit, 114...waste crane, 120...combustion equipment, 121...waste input hopper, 122...combustion furnace, 123...grate, 12 4...Dust feeding equipment, 125...Drying zone, 126...Combustion zone, 127...Post-combustion zone, 128...Combustion air, 129...High-temperature gas, 130...Boiler equipment, 131...Water supply pipe, 132...Boiler, 133...Evaporation tube, 134...Brackish water drum, 135...Steam piping, 136...Superheater, 137...Superheater tube, 138...Economizer, 139...Reheater tube, 140...Power generation equipment, 150...Exhaust gas cooling tower, 160...Dust collector, 161...Bag filter, 169...Dust collection hopper, 170...Chimney, 180...Ash removal equipment.

Claims

1. a hollow hydrogen permeation recovery tube made of a metal or alloy and selectively permeable to hydrogen, the tube being disposed at least on the grate of the stoker furnace; a hydrogen storage unit; a negative pressure means for creating a negative pressure in the internal space of the hydrogen permeation recovery pipe in order to transfer hydrogen from the internal space to the hydrogen storage section; A hydrogen recovery system comprising:

2. 2. The hydrogen recovery system according to claim 1, wherein the hydrogen permeation recovery pipe is made of a material that allows hydrogen to permeate at temperatures of 300°C or higher.

3. 3. The hydrogen recovery system according to claim 1, wherein the hydrogen permeation recovery pipe is corrosion resistant.

4. 3. The hydrogen recovery system according to claim 1, wherein the hydrogen permeation recovery pipe is a stainless steel pipe.

5. 3. The hydrogen recovery system according to claim 1, wherein the hydrogen permeation recovery pipe is disposed on at least a main surface of a fixed grate of the stoker furnace.

6. 3. The hydrogen recovery system according to claim 1, wherein the stoker furnace includes at least a drying zone and a combustion zone, and the hydrogen permeation recovery pipe is installed in at least the drying zone.

7. The hydrogen recovery system according to claim 6, wherein the hydrogen permeation recovery pipe is also installed in the combustion zone.

8. a grate for conveying waste; a hollow hydrogen permeation recovery tube made of a metal or alloy that is selectively permeable to hydrogen and that is disposed at least on the fire grate; a hydrogen storage unit; a negative pressure means for creating a negative pressure in the internal space of the hydrogen permeation recovery pipe in order to transfer hydrogen from the internal space to the hydrogen storage section; A stoker furnace equipped with:

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